1. Field of the Invention
The present invention relates to a probe card that adopts wirings in place of a multilayer ceramic substrate as a space transformer. More particularly, the present invention relates to a probe card, which is provided with a sub-circuit board for connecting a main circuit board and a space transformer to each other, and thus facilitates a wiring connection work to reduce a working time and to prevent a working error.
2. Description of the Prior Art
In general, a semiconductor device is manufactured through a fabrication process forming a pattern on a wafer and an assembly process assembling the patterned wafer into respective chips.
Between the fabrication process and the assembly process, a process so called an EDS (Electrical Die Sorting) testing electrical characteristics of respective chips, that is, semiconductor devices (DUT), that constitute a wafer is interposed, and this EDS process is performed to discriminate inferior semiconductor devices from semiconductor devices that constitute the wafer.
An electrical test of semiconductor devices that constitute a wafer is performed mainly using a test device that is called a probe card having plural probes which become in contact with the respective semiconductor devices to apply electrical signals thereto.
A typical probe card includes a main circuit board, a space transformer (STF), and probes fixedly attached to the space transformer. Here, as the space transformer, a multilayer ceramic (MLC) is mainly used.
On the other hand, if the wafer has a large area, it is required to manufacture a probe card of which the area is equal to or larger than a test area of the wafer. In this case, a space transformer having a large area is manufactured in the related art. However, since the MLC is expensive, it costs too much to manufacture the MLC having the large area.
In order to supplement this, as illustrated in FIG. 1, a wire type probe card that does not use the MLC, as the space transformer has been proposed. As illustrated in FIG. 1, such a probe card briefly includes a main circuit board 2, a space transformer 3 positioned on a lower portion of the main circuit board 2, and a wire unit 4 connecting the main circuit board 2 and the space transformer 3 with each other. In this case, both ends of the wire unit 4 are fixedly soldered to the main circuit board 2 and the space transformer 3, respectively, and the soldered wire unit 4 of the space transformer and the wafer are electrically connected by a pogo pin 5. This pogo pin 5 provided on both sides of the main circuit board 2 serves to connect the main circuit board 2 and semiconductor test equipment (not illustrated) positioned on an upper portion of the main circuit board 2 with each other.
However, since the wire unit 4 of the probe card, which is composed of a bunch of wires, is soldered to the space transformer 3, it is hard to connect the wires to the main circuit board 2 one by one, and it requires a lot of working time. Further, interference such as piling up of the wires may occur and a working error may be increased.
Further, since the wire unit 4 that connects the space transformer 3 and the main circuit board 2 with each other has a long length, a semiconductor testing speed is lowered.